The present disclosure relates to a power conversion device that converts electric power between DC power and AC power of a plurality of phases.
Metal oxide semiconductor field effect transistors (MOSFETs), insulated gate bipolar transistors (IGBTs), and the like are known as switching elements to be used for power circuits such as an inverter. The MOSFET and the IGBT have different electric characteristics because of differences in terms of physical properties and structures. In general, the power circuit such as an inverter is structured by switching elements of the same type. Attempts have been made to achieve an electrically wide application range by structuring a circuit in which a plurality of types of switching element are mixed with use of the differences in terms of the electric characteristics of the switching elements. Japanese Patent Application Publication No. 2012-253202 from a source described below discloses a power module (switching elements) in which the MOSFET and the IGBT are connected in parallel in the same package.
FIG. 1 and FIG. 4 of Japanese Patent Application Publication No. 2012-253202 exemplify conceptual diagrams in which control lines are individually provided for a control terminal of the MOSFET and a control terminal of the IGBT. A specific control method is described with reference to FIG. 2. Specifically, the same control signal having two-stage positive voltage levels is supplied to the control terminals of both of the elements, thereby performing control for a case where only the MOSFET is operated and a case where the MOSFET and the IGBT are operated. The technology disclosed in Japanese Patent Application Publication No. 2012-253202 is excellent in that the switching elements having different electric characteristics can selectively be used in accordance with conditions. In the example specifically demonstrated in Japanese Patent Application Publication No. 2012-253202, however, the same control signal is used for control even though the switching elements having different electric characteristics are switched individually. Therefore, it is difficult to more finely control the switching timings of both of the switching elements. There is room for a further increase in efficiency in consideration of an entire system including various circuit components provided together with an inverter circuit and a target to which AC power is supplied by the inverter circuit.